While the present invention has been developed and is described in terms of its use in the oilfield, those of ordinary skill in the art will understand that the disclosed system and method may be used in a variety of applications where extended length objects must be relocated from one position to another.
Those with experience in the oilfield are familiar with those wells into which long sections of pipe are screwed together and inserted into the well as a long pipe string. Typically, workers on a rig floor positioned over a well bore perform the task of receiving a section of pipe from a temporary storage location near the well, elevating the section of pipe to a substantially vertical position, and then threadably connecting the elevational section of pipe to another section of pipe which has been partially inserted into the well bore. The threadably joined sections of pipe eventually form a continuous pipe string which extends from above the earth's surface to the bottom portion of the well.
The derrick or large structure which provides a signature appearance to an oil rig positioned over a well bore facilitates the lifting of an extended length section of pipe to a substantially vertical position. Once in a vertical position, the extended length section of pipe is threadably connected to another section of pipe lower in the pipe string.
When a pipe string is pulled out of the well bore to either service or close down a well the process described above is effectively reversed. Specifically, as each section of pipe is pulled from the well bore, it must be first threadably disconnected from the next lower section of pipe in the pipe string before being moved out the way and placed in storage while the next lower section of pipe is extracted from the well bore.
For many years the activity of moving sections of pipe between a storage location near the well to a location over the well bore was an operation that well hands performed manually. Because of the weight of the sections of pipe and the speed of the activity on a rig floor, well hands often become fatigued or injured. In other situations, well hands have either lost control of or dropped a section of pipe, causing either damage to valuable equipment or injuries to other workers.
A further description of the problems and dangers associated with manually moving sections of pipe near an oil rig may be found in U.S. Pat. No. 4,386,883 and U.S. Pat. No. 6,079,925.
Both U.S. Pat. No. 4,386,883 and U.S. Pat. No. 6,079,925 describe the use of a large machine which operates by mounting a section of pipe in a long trough. In both patents the long trough is positionable by being mounted to a frame whose vertical height, at one end, is controllable. Movement of the section of pipe along the long trough is accomplished by use of a pusher. The pusher provides a force on the lower end of the section of pipe to cause the section of pipe to slide along the long trough far enough to place the upper end of the section of pipe in a desired location. Because the long trough is nearly as long as the section of pipe, the frame which supports the long trough is also nearly as long as the sections of pipe. For large wells, this length can be as much as 50 feet.
Those with experience in the oilfield know that sections of pipe are often transported on long semi-trailers to the site of an oil rig. The transport of the devices described in U.S. Pat. No. 4,386,883 and U.S. Pat. No. 6,079,925 to an oil rig also requires use of a long trailer. Then, once at the site of an oil rig, a major effort is required to first unload and then position the devices described in U.S. Pat. No. 4,386,883 and U.S. Pat. No. 6,079,925 into a location near both the rig floor and the area in which the sections of pipe destined for insertion into the well bore are temporarily stored. When the movement of sections of pipe has been completed another major effort is required to move the devices away from the rig floor and onto a long trailer for use at the site of another oil rig. The effort to move the devices described in U.S. Pat. No. 4,386,883 and U.S. Pat. No. 6,079,925 is both time-consuming and expensive.
Accordingly, a need remains in the art for a system and method which can quickly, easily and inexpensively be put in position to move extended length objects, such as sections of pipe, into locations where they can be further handled or put in place for their desired purpose.